α-Glucosidase (EC 3.2.1.20, maltase, glucoinvertase, glucosidosucrase, maltase-glucoamylase, α-glucopyranosidase, glucosidoinvertase, α-D-glucosidase, α-glucoside hydrolase, α-1,4-glucosidase, α-D-glucoside glucohydrolase; systematic name α-D-glucoside glucohydrolase) is a glucosidase located in the brush border of the small intestine that acts upon α(1→4) bonds: Hydrolysis of terminal, non-reducing (1→4)-linked α-D-glucose residues with release of D-glucose This is in contrast to β-glucosidase. α-Glucosidase breaks down starch and disaccharides to glucose. Other glucosidases include: Cellulase Beta-glucosidase Debranching enzyme Mechanism α-Glucosidase hydrolyzes terminal non-reducing (1→4)-linked α-glucose residues to release a single α-glucose molecule. α-Glucosidase is a carbohydrate-hydrolase that releases α-glucose as opposed to β-glucose. β-Glucose residues can be released by glucoamylase, a functionally similar enzyme. The substrate selectivity of α-glucosidase is due to subsite affinities of the enzyme's active site. Two proposed mechanisms include a nucleophilic displacement and an oxocarbenium ion intermediate. Rhodnius prolixus, a blood-sucking insect, forms hemozoin (Hz) during digestion of host hemoglobin. Hemozoin synthesis is dependent on the substrate binding site of α-glucosidase. Trout liver α-glucosidases were extracted and characterized. It was shown that for one of the trout liver α-glucosidases maximum activity of the enzyme was increased by 80% during exercise in comparison to a resting trout. This change was shown to correlate to an activity increase for liver glycogen phosphorylase. It is proposed that α-glucosidase in the glucosidic path plays an important part in complementing the phosphorolytic pathway in the liver's metabolic response to energy demands of exercise. Yeast and rat small intestinal α-glucosidases have been shown to be inhibited by several groups of flavonoids. Structure α-Glucosidases can be divided, according to primary structure, into two families. The gene coding for human lysosomal α-glucosidase is about 20 kb long and its structure has been cloned and confirmed. Human lysosomal α-glucosidase has been studied for the significance of the Asp-518 and other residues in proximity of the enzyme's active site. It was found that substituting Asp-513 with Glu-513 interferes with posttranslational modification and intracellular transport of α-glucosidase's precursor. Additionally, the Trp-516 and Asp-518 residues have been deemed critical for the enzyme's catalytic functionality. Kinetic changes in α-glucosidase have been shown to be induced by denaturants such as guanidinium chloride (GdmCl) and SDS solutions. These denaturants cause loss of activity and conformational change. A loss of enzyme activity occurs at much lower concentrations of denaturant than required for conformational changes. This leads to a conclusion that the enzyme's active site conformation is less stable than the whole enzyme